1. Field of the Invention
This invention relates to a robot, and more particularly, to an articulated robot which is especially useful for performing arc welding in a desired position.
2. Description of the Prior Art
A known arc welding robot comprises a stationary table fixed on a floor, a rotary table mounted rotatably on the stationary table, a motor mounted on the stationary table for rotating the rotary table, a front arm carrying a welding torch at its free end, and an upper arm provided tiltably on the rotary table for supporting the front arm. The welding torch and the front and upper arms are tilted, and the rotary table is rotated, as required for bringing the robot into a proper position for arc welding. An improved arc welding robot has a plurality of sensors provided at the free end of its front arm, and an additional number of shafts. These sensors and shafts create a large load bearing on the upper arm, and necessitates the use of a motor having a large capacity for driving the upper arm. The use of a hydraulic or pneumatic device has been proposed for reducing the load bearing on the upper arm driving motor. The addition of any such extra device, however, results in an undesirably large and complicated robot.